Such receivers may include processing means provided with a memory and a comparator and able to execute an iterative process during each step of which it derives from a signal of the burst received from the substation a decision threshold related to a characteristic of the signal. The threshold is stored in the memory and the characteristic is compared in the comparator with a previous threshold which has been determined and stored in the memory for the substation during a previous step of the process and which is applied to the comparator.
The receiver of such a system, which is generally known in the art, is described in the article "Burst-Mode Compatible Optical Receiver With A Large Dynamic Range", by Yusuke Ota and Robert G. Swartz, published in the "Journal of lightwave technology", Vol. 8, No 12, December 1990, pp. 1897-1905. Therein the processing means determines the amplitude threshold value used to convert a received analog signal to a digital signal "on the fly", i.e. at the beginning of each burst of signals. For high-rate burst signals this implies that the processing means has to perform this operation at a correspondingly high speed and therefore has to be equipped with components allowing such a high speed operation, such components being generally expensive. Moreover, the: known receiver cannot be applied in so-called point-to-multipoint systems.